Method of making molders&#39; patterns.



J. P. COX. v METHOD 0F MAKING MOLDERS PATTERNS.

APPLICATION FILED APR. 8, 1908.

Patented Sept. 15, 1908. 2 sHEBTssHEET 2` U21/@messes l JOSEPH F. COX,OF WATERTOWN, MASSACHUSETTS.

METHOD OF MAKING MOLDERS PATTERNS.

Specification of Letters Patent.

Patented sept. 15, 190s.

Application mea April s, 190s. serial Nn. 425,829.

To all whom it may concern:

Be it known that I, JOSEPH F. COX, of Watertown, in the county ofMiddlesex and State of Massachusetts, have invented certain new anduseful Improvements in Methods of Making Molders Patterns, of which thefollowing is a specification.

This invention relates to a method of making metal patterns which areused by molders or founders for the production of cast metal ware whichshall possess a substantially uniform thickness regardless of the amountof ornamentation to be presented by the surface of the plate.

The especial object of my invention is to obtain a hollow pattern ofeven thickness from a solid or block pattern without requiring anymanual operation of backing out the original wood pattern.

While my invention is capable of being utilized f`or the production ofornamental cast metal ware in general, it has been designed withespecial reference for the production of stove patterns. As is wellknown, many portions of a stove are made of thin cast metal, the platesor ornamental sections being made quite thin, such as or 6 of an inch inthickness, it being necessary to cast metal thin in order to producegood surfaces on the castings. Heretofore, so far as I am aware, thewood patterns used for this class of work have required the employmentof wood carvers of considerable experience to back out or shell the woodpattern to reduce it to a substantially uniform thickness, the backingout being made of course to correspond with the raised ornamentalportions on the face of the pattern. This work requires not only a highdegree of skill but it is slow, because of the constant calipering ofthe wood. Frequently it takes a wood carver three days or more to backout" or shell one wood pattern. My invention enables a master metalpattern to be produced by means of the face only of the original woodpattern, the work of the carver who Hbacks out or shells the patternbeing therefore dispensed with.

In the accompanying drawings I have illustrated'some of the stepsfollowed in practicing my improved method. Each of the Figures l to 5inclusive, is a sectional view illustrating not only the steps of themethod but parts of the usual molders apparatus which may be employed inpracticing the invention.

I first place the'solid pattern a on the bottom or mold board of a flaskb, preferably securing it by any suitable means on the bottom board. Ithen coat the upper face of the pattern and the inside of the flask withany suitable oil such as linseed oil, to prevent the plaster of paris,which is afterwards used, from adhering to the pattern and ask. So farthe invention may be considered as illustrated in Fig. 1. I then pourplaster of paris into the flask to cover the upper surface of the woodpattern to a considerable thickness as indicated in Fig. 2, wherein thesaid plaster of paris is indicated at c. In order to hold the plaster ofparis firmly within the sides of the flask after the latter has beeninverted, as hereinafter described, any suitable supporting means suchas braces d may be embedded in the plaster of paris before it has set,the ends of the braces being secured to the sides of the fiask or heldin any suitable way. When flask is inverted and the bottom or mold boardand the pattern are removed, the concave surface of the plaster of parisbeing then resented uppermost as indicated in Fig. 3.

then i'ill or partially fill the concavity with water so as to uniformlycool the plaster. If the concavity is not completely filled, the waterwill be dashed around so as to practically uniformly moisten or cool allof the surface. Most of the water can be then permitted to soak into theplaster of paris. Having thus obtained a uniformly cooled moldingsurface of laster of paris, I fill the concavity with me ted `wax andleave the same long enough for a film to solidify in contact with theconcavity of the plaster. I have found, in practice, that with thesurface of the plaster chilled to some 60, a solidified waX film ofabout lg of an inch thick will form in thirty to forty seconds. I thenpour out the surplus wax, leaving a film of waX e as indicated in Fig.4, which film will be practically of uniform thickness and will possessan inside and an outside configuration conforming to the surface of theoriginal pattern a. Of course the thickness of the film or wax pattern ewill depend upon the relative temperatures of the plaster of paris andwax when first brought together, and upon the length of time that thewaX is the plaster of paris has set, the y left in the position shown inFig. 3 before being tipped or poured out. The marginal portions f of thewax film are trimmed off, the wax pattern being left supported by theplaster.

The neXt step is not illustrated as it will be readily understood fromthe following description. The founder uses the wax pattern e to get hiscope impression in sand, and the original pattern is employed in theusual way to get the nowel impression in sand. The cope and nowel arethen assembled in the usual manner as indicated in Fig. 5, the space.between the two corresponding of course to the thickness that was givento the waX pattern or iilm c.

In Fig. 5 I have not attempted to illustrate the opening by which thecast metal is introduced into the space as the same will be readilyunderstood without further description. This first casting of courseproduces a master pattern from which any number of duplicates can bemade in the usual manner of the founders art.

As will now be apparent my improved method completely takes the place ofbacking out or shelling of the original wood pattern, enabling the facealone of the latter to be employed to produce both sides of a castingwhich is then used as the master pattern.

It will be understood of course that the Wax which is the only expensivematerial which I employ, may be melted and used repeatedly. The plasterof paris of course is roken up and thrown away.

1I claim :k

1. The method of making an ornamental casting of substantially uniformthickness, consisting in making a plaster cast from the pattern, fillingthe cavity in the cast with a Huid material capable of hardening to athickness varying according to its temperature and the period of contactwith the cast whereby a lining is formed in the cast, pouring off thesurplus or unhardened material, producing sand molds from the saidlining and the pattern, and then assembling the sand molds and castingmetal between them.

2. The method of making an ornamental casting of substantially uniformthickness, consisting in making a plaster cast from the pattern,.uniformly chilling the plaster cast, then lining the chilled cast withwax, producing sand molds from the wax lining and the pattern, and thenassembling the sand molds and casting metal between them.

3. The method of making an ornamental casting of substantially uniformthickness, consisting in making a plaster cast from the pattern, wettingthe plaster cast to uniformly chill it, lining the chilled cast withwaX, producing sand molds from the wax lining and the pattern, and thenassembling the sand molds and casting metal between them.

4. The method of making a metal pattern of substantially uniformthickness, said method including molding a reverse ofthe face of a woodpattern, treating saidreverse to cause all of its surface topossess asubstantially uniform temperature, filling the cavity, of said reversewith a iuid material capable of hardening by contact with said reverseto form a film, pouring off the surplus or unhardened material, and thenmaking a crlipe impression from the inner surface of the fi m.

5. The method of making a metal pattern of substantially uniformthickness, consisting in forming a molded reverse of the face of a blockpattern, treating said reverse tocause all of its surface vto possess asubstantially uniform temperature, filling the cavity of said reversewith a fluid material capable of hardening by contact with said reverseto l form a film, pouring off the surplus or un- I hardened material,then making the cope and l nowel impressions from the iilm and blockpattern respectively, and then casting a metal pattern from saidimpressions.

6. The method of reproducing the face of a wood pattern to form bothsurfaces of a metal pattern, said method consisting lin forming a moldedplaster of paris reverse of the block pattern, wetting the moldedplaster to uniformly chill it, lining said molded reverse with a waxfilm, then makingthe cope and nowel impressions from the film and blockpattern respectively, and then casting a metal patternv fromsaidfimpressions.

In testimony whereof I have aflixedvmy signature, in presence of twowitnesses.

JOSEPH F. COX. Vitnesses:

F. R. RoULsToNE, P. W PEZZETTI.

